Priority is claimed to Japanese Application Nos. 10-171208 and 10-276867 filed in Japan on Jun. 18, 1998 and Sep. 30, 1998, respectively, both of which are herein by reference.
1. Field of the Invention
The present invention relates to a monitor display apparatus for non-contacting 3-D measurement and generation of a 3-D model based on the 3-D measurement.
2. Discussion of Related Art
A non-contacting 3-D measuring apparatus termed a xe2x80x9crange finderxe2x80x9d has been used for inputting data to a CG (computer graphics) system or a CAD (computer aided design) system, human body measurement, visual recognition by a robot, and the like since it can perform higher-speed measurement than a contacting measuring apparatus.
Non-contacting 3-D measurement methods can be subdivided into an active method such as a light chopping method or a pattern projection method and a passive method represented by a stereovisual method. In a light chopping method (also termed slit-light projection method), for example, a slit light beam having a rectilinear cross section is projected as a reference beam on an object such that the slit light beam is polarized and used to scan the object. From the angle at which the slit light beam is projected and the angle at which the slit light beam reflected by the object is incident upon a light receiving surface, the distance between a reflection point on the object and a reference point in the apparatus can be calculated on the principle of triangulation. If the distance is calculated for each pixel on the light receiving surface, a distance image representing the configuration of the object can be obtained.
In accordance with any of the foregoing various measurement methods, a part of the target object cannot be measured depending on the configuration of the object or on the positional relationship between the object and the measuring apparatus. When an object having a highly irregular configuration is measured in the active method, a shaded portion is produced in a region observed from the light receiving surface, and the shaded portion is unmeasurable because the reference beam is not projected thereon. Even when the highly irregular object is measured in the passive method, a portion observable only with either of right and left image pickup devices is produced, which is also unmeasurable.
Depending on the position and size of such an unmeasurable portion (referred to as an xe2x80x9cerror regionxe2x80x9d), there may be cases where measurement should be performed again. However, the conventional measurement methods have the problem that, even when the measurer views the distance image monitored on the display disposed in the measuring apparatus or connected thereto as an external device, it is difficult for the measurer to recognize the position and size of the error region. In some instances, the measurer recognizes the error region only after a surface model was produced based on measurement data. If considerable time has elapsed from the measurement, the target object may not be on the spot of measurement when measurement is to be performed again.
It is therefore an object of the present invention to facilitate the recognition of the error region on the target object in 3-D measurement.
To achieve this and other objects, the present invention can be embodied as an apparatus which includes a display for displaying an image; means for recognizing, based on 3-D data obtained by measuring an object in three dimensions, an error region which is an unmeasurable portion of the object in a measured range; means for extracting a partial image corresponding to the error region from a 2-D image obtained by imaging the object; and display control means for displaying a monitor image representing at least the size and position of the partial image on the display.
According to this invention, it becomes possible to easily recognize the error region on the target object in 3-D measurement.
The display control means can display the monitor image obtained by performing specific image processing with respect to the partial image.
The display control means can display the 2-D image with the partial image being enhanced as the monitor image.
Additionally, the present invention an be embodied as an apparatus which includes a display for displaying an image; means for recognizing, based on 3-D data obtained by measuring a head in three dimensions, an error region which is an unmeasurable portion of the head; and display control means for displaying, on the display, a 2-D image obtained by shooting the head after performing specific image processing with respect to a region thereof corresponding to skin which is also a portion corresponding to the error region.
Such processes as error region recognition, partial image extraction, and image processing can be performed by either a hardware circuit using various electronic devices or a function implemented by a computer or microprocessor for executing a program, or varying combinations of both. It is sufficient for the target object to be present at the time of 3-D measurement. The object may be a human face, a human head, another human body part, a living thing other than a human, or a nonliving thing. It is sufficient for the 3-D data to specify the configuration of the portion of the object other than the error region such that it is reproducible. The 3-D data may be a distance image, a variety of models in 3-D configurations, or a measurement original data forming a base for distance calculation. Although the 2-D image is preferably a color image, it presents no obstacle to the display of an error even if the 2-D image is a monochrome image. As examples of the image processing performed with respect to the partial image or the like, there are solid painting in a specific color, pattern painting, contouring, and the like. As examples of enhancement, there are color change, solid painting, brightness change, flashing, and the like.
According to the invention recited, it becomes possible to prevent, in displaying a 2-D image obtained by shooting the head, the portion of the error region that can be recovered in 3-D measurement from being displayed. As a result, only an intrinsic error region can be recognized.